Thank you for your inputs! I accidentally forgot to add, but I studied about OTP, too. I studied that although it is considered theoritically uncrackable, in practice no key can be kept in perfect secret. So, it is very good in theory, but I wonder if there are better encryptions that work better in PRACTICE.
As for AES256: I studied a bit about AES, but not much about AES256. However, I found it in NSA Suite B. What does that mean to us?
Not much really as far as NSA is concerned, it just means it meets their standard for classified data. What you really want to look at is FIPS 197 from NIST to get the details on AES. Government DoD programs for unclassified (and occasionally classified) data will reference a set a standards, typically FIPS.
http://csrc.nist.gov/publications/fips/fips197/fips-197.pdfTo learn about the practical applications of how a cryptographic module may be used for government systems, the requirements are in (more so for US Government DoD programs) FIPS 140-2.
http://csrc.nist.gov/publications/fips/fips140-2/fips1402.pdfSo, I used to work for NASA and now deal with other government entities, in practice, AES256 is used to encrypt data, the pragmatic approach for exchange is to use PGP (OpenPGP for example). Just be careful with exchanging the
public key to avoid man in the middle attacks.